/* Copyright 2017 The TensorFlow Authors. All Rights Reserved.
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License.
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==============================================================================*/
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#ifndef TENSORFLOW_CORE_UTIL_PERMUTATION_INPUT_ITERATOR_H_
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#define TENSORFLOW_CORE_UTIL_PERMUTATION_INPUT_ITERATOR_H_
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#include <iostream>
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#include <iterator>
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namespace tensorflow {
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template <typename ValueType, typename InputIteratorT, typename IndexIteratorT,
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typename OffsetT = ptrdiff_t>
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class PermutationInputIterator {
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public:
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// Required iterator traits
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typedef PermutationInputIterator self_type; ///< My own type
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typedef OffsetT difference_type; ///< Type to express the result of
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///< subtracting one iterator from another
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typedef ValueType
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value_type; ///< The type of the element the iterator can point to
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typedef ValueType* pointer; ///< The type of a pointer to an element the
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///< iterator can point to
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typedef ValueType reference; ///< The type of a reference to an element the
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///< iterator can point to
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typedef std::random_access_iterator_tag
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iterator_category; ///< The iterator category
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private:
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InputIteratorT input_itr;
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IndexIteratorT index_itr;
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public:
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/// Constructor
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__host__ __device__ __forceinline__ PermutationInputIterator(
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InputIteratorT input_itr, ///< Input iterator to wrap
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IndexIteratorT index_itr) ///< Conversion functor to wrap
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: input_itr(input_itr), index_itr(index_itr) {}
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/// Postfix increment
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__host__ __device__ __forceinline__ self_type operator++(int) {
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self_type retval = *this;
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index_itr++;
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return retval;
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}
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/// Prefix increment
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__host__ __device__ __forceinline__ self_type operator++() {
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index_itr++;
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return *this;
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}
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/// Indirection
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__host__ __device__ __forceinline__ reference operator*() const {
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return input_itr[*index_itr];
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}
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/// Addition
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template <typename Distance>
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__host__ __device__ __forceinline__ self_type operator+(Distance n) const {
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self_type retval(input_itr, index_itr + n);
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return retval;
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}
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/// Addition assignment
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template <typename Distance>
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__host__ __device__ __forceinline__ self_type& operator+=(Distance n) {
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index_itr += n;
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return *this;
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}
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/// Subtraction
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template <typename Distance>
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__host__ __device__ __forceinline__ self_type operator-(Distance n) const {
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self_type retval(input_itr, index_itr - n);
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return retval;
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}
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/// Subtraction assignment
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template <typename Distance>
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__host__ __device__ __forceinline__ self_type& operator-=(Distance n) {
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index_itr -= n;
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return *this;
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}
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/// Distance
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__host__ __device__ __forceinline__ difference_type
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operator-(self_type other) const {
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return index_itr - other.index_itr;
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}
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/// Array subscript
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template <typename Distance>
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__host__ __device__ __forceinline__ reference operator[](Distance n) const {
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return input_itr[index_itr[n]];
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}
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/// Structure dereference
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__host__ __device__ __forceinline__ pointer operator->() {
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return input_itr + *index_itr;
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}
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/// Equal to
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__host__ __device__ __forceinline__ bool operator==(const self_type& rhs) {
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return (index_itr == rhs.index_itr && input_itr == rhs.input_itr);
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}
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/// Not equal to
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__host__ __device__ __forceinline__ bool operator!=(const self_type& rhs) {
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return !(*this == rhs);
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}
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/// ostream operator
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friend std::ostream& operator<<(std::ostream& os, const self_type& itr) {
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return os;
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}
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};
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} // end namespace tensorflow
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#endif // TENSORFLOW_CORE_UTIL_PERMUTATION_INPUT_ITERATOR_H_
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